1. Field of the Invention
The present invention is related to a confining ring set suiting wider range of diameter of pipes, and especially the common pipes connected with each other coaxially, including straight pipes or tapered pipes of various diameters telescopically connected mutually, so that a confining ring set of the present invention can be fitted directly over the external wall of an exterior pipe of which the diameter can be various.
2. Description of the Prior Art
Common pipes connectable with each other coaxially seen in the markets nowadays include those such as posts for bicycles, pipes for taps, stretchable pipes for flag poles, stretchable pipes for umbrellas and stretchable connecting pipes for fishing nets etc.; normally an inner as well as an outer pipe connectable with each other coaxially are loosely placed together, every connecting area on these inner as well as outer pipes is provided with a confining device, so that when the inner and outer pipes are telescopically adjusted to a desired length or height, the confining device can fixedly confine the inner and outer pipes in positions.
However, confining devices used for pipes connected with each other coaxially can be seen in the techniques used in the arts, the disadvantages thereof are now described below:
1) As to those which lock pipes for positioning through contact of a plurality of points: normally a screw or more than one screws are used to contact an exterior pipe at a connection of the pipes, and are threadedly feeded, then the screw ends press directly the exterior wall of an interior pipe, thereby tight clamping for fixed positioning of the interior pipe by contact of one or a plurality of points can be effected; conventional articles use such way for clamping tight can be seen normally on stretchable pipes for flag poles wherein the exterior pipes have thick walls or on stretchable pipes for umbrellas having less load; locking by one point contact can be enhanced by increasing screws to form a three point contact mode to achieve circumferential confining, however, point contact can not effectively confine the interior pipe which is full of stress at every part of the whole periphery thereof, the articles such as stretchable pipes for flag poles have very long length and very heavy weight, they also bear external forces such as wind force, the force of gravity or other component forces, the moment formed on such long pipes may induce very large and non-directional stress at the connection of the pipes, therefore, clamping by screws for fixed positioning of an interior pipe by contact of points can not deal with all the equalized stress on the peripheral wall of the interior pipe at the connection, this is the reason why the pipes are subjected to loosening. PA1 2) As to those which lock pipes for positioning through surface contact: normally a "C" shaped confining ring is used, screws are provided on the wall portions at both sides of the opening of the "C" shaped confining ring for reducing the diameter of the confining ring and thus contracting the exterior wall of the exterior pipe, so that the exterior wall of the interior pipe is clamped tight for fixed positioning thereof; conventional articles use such way for clamping tight can be seen normally on posts for bicycles and pipes for taps; the wall of a "C" shaped confining ring has a confining area which is almost equal to the peripheral area of an imaginary similar ring without an opening and thus can form friction drag with the exterior wall of the interior pipe with a relatively larger contact area, so that the interior pipe can be effectively tightly confined; however, the "C" shaped confining ring itself only has a limited confining range, and the curvature created in confining is not truly round, therefore, its confining action force in clamping the interior pipe through the exterior pipe is not uniformly distributed in the whole periphery of the interior pipe, a problem of unability of effective confining thus exists; if a post for a bicycle or a pipe for a tap wherein a confining ring has to bear the weight of a man and vibration during riding or pressing of an arm of a man can not get an effective confining function for a long period, loosening at the connection of the pipes will induce accidental hurt or inconvenience sooner or later.
The above stated two conventional measures of locking or confining are not able to effectively get the function of confining a connection of an interior and an exterior pipe; and although confining effect obtained by surface contact can be better than that obtained by point contact, in addition to not exactly round surface contact, conventional confining rings have the defect of limited confining range, so that confining rings of single diameter gauge are not good enough for use with pipes of various diameters to be assembled and confined, practicality thereof thus is relatively low. This may be seen on a post for a bicycle or a pipe for a tap, exterior pipes in the markets are of the gauge of diameter of .phi.25.4-31.8 mm, such range is out of the limited range of confining, hence manufacturers must make products of various sizes for application, this increases quite much cost, the invention is an improvement directing to these problems and inconvenience.